My 03 5.9 dakota with a 46re is making a rattling noise around 45-50 mph. Only when accelerating as well. It has always done that since i swapped the 5.9 into her. So i thought it might have been the torque converter anyway bc i was getting the p1740 code. This isn’t about that tho so long story short i replaced the torque converter with a factory one, left the torque converter shield off bc that was another suspect and it’s still making that damn rattle noise. It’s not a heat shield. I believe it to be coming from the starter (which it is tight don’t worry) if that’s even possible. When i did my torque converter i noticed inside the case where the starter recedes, it was cracked a little bit and a chunk was missing from the previous time i left the starter loose lol. It isn’t anything major like causing a leak, wish i took a picture but anyways any help would be greatly appreciated, Thanks

 

Does it sound like marbles in a tin can? Might be spark knock.... Has the plenum been fixed? Take a look down the throttle body. (engine off...) See any oil pooling in there?

 

Funny you say that lmao, i rebuilt this 5.9 and obviously put a new plenum gasket in. The other day i looked in there and did see a puddle of oil in there. I’m assuming the plenum plate is warped? It does sound like marbles in a tin can

 

That could be spark knock. Disable the PCV system, plug the port in both the intake, (for the valve) and the hose that goes to the air box. Take off the oil cap, start the engine, let it run at idle. Check the oil fill hole. Got a breeze coming out? Or is there vacuum there?

 

There is a breeze coming out

 

Ok, that's the way it should be.

Ever done a seafoam treatment? Feed the engine seafoam via the vacuum line for the brake booster. Make sure you don't feed it too much though.... I had my son hold the engine at about 1200 rpm, while I put the tube close to the liquid surface, so it would just suck a little in at a time, and let the motor ingest most of the bottle, let the engine stall, and sit for 10 minutes, and on restart, there was a HUGE cloud...... (if you live in an urban area, don't do this at home, your neighbors will be powerful unhappy. )

 

LOL i will most definitely try it today and update you, just regular seafoam? Bc i know they have like 10 different variants now

 

Yep. Just the regular stuff.

 

Dakota took the whole bottle but i didn’t read your message carefully. Had my gf on the throttle keeping it at 1200 rpm and it sucked down my whole bottle of sea foam, i didn’t let it stall tho. Smoked up my whole neighborhood lmao but after it was done smoking i took it on a drive and it was still pinging, looked down the throttle body into the plenum and it looks like the sea foam got all of the oil out! I’ll keep driving it and lyk i’m waiting on hughes engines to send me the plenum fix

 

Just replaced my plenum with the hughes one, spark knock is still there. Any other suggestions while i’m dumping all my money into a spark knock lol